Underwater Surveillance
First Claim
1. An underwater surveillance system including:
- a sensor array subsystem configured and arranged for immersion in a body of water to transmit and receive sonar signals and comprising a plurality of piezoelectric elements arcuately spaced apart azimuthally around an angle θ
;
a data acquisition subsystem operatively connected to the sensor array subsystem to digitise data therefrom; and
a beamforming subsystem operatively connected to the data acquisition subsystem;
wherein the beamforming subsystem is operative to process outputs of the sonar array subsystem by means of a pseudo-circular convolution technique thereby to form defined beams.
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Abstract
A counter-terrorism underwater surveillance system for detecting swimming intruders includes a sonar array 20 comprising a plurality of sensor elements which both transmit and receive acoustic signals. Power amplifiers 22 generate electric transmit signals which are converted to acoustic form for transmission by the sonar array 20. Incoming acoustic signals, including echo data from any intruder in the water, are received by the sonar array 20 and passed to a data acquisition subsystem 24, which digitises the data for processing. The digitised data is passed to a beamforming subsystem 26 which forms defined beams from omni-element data. A detection processing subsystem 28 then extracts signals from noise and reverberation and passes these to a display processing subsystem 30 which defines tracks from the intruder echo data. Finally, intruder images and tracks are displayed on a display subsystem 32. The beamforming subsystem processes outputs of the sonar array subsystem by means of a pseudo-circular convolution technique thereby to form defined beams.
52 Citations
41 Claims
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1. An underwater surveillance system including:
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a sensor array subsystem configured and arranged for immersion in a body of water to transmit and receive sonar signals and comprising a plurality of piezoelectric elements arcuately spaced apart azimuthally around an angle θ
;a data acquisition subsystem operatively connected to the sensor array subsystem to digitise data therefrom; and a beamforming subsystem operatively connected to the data acquisition subsystem; wherein the beamforming subsystem is operative to process outputs of the sonar array subsystem by means of a pseudo-circular convolution technique thereby to form defined beams.
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2-22. -22. (canceled)
- 23. A beamformer for forming defined beams by processing signals from a sensor array, wherein said beamformer includes pseudo-circular convolution means for processing said signals.
Specification